FEASIBILITY OF CYSTATIN C DETERMINATION FOR EARLY DIAGNOSIS OF KIDNEY DAMAGE IN PATIENTS WITH TYPE 2 DIABETES COMBINED WITH NONALCOHOLIC FATTY LIVER DISEASE AND OBESITY EXPOSED TO COVID-19 INFECTION IN THE PAST

The aim: To examine the diagnostic possibilities of determining the level of cystatin C in the blood serum in order to ascertain the functional status of the kidneys in patients with type 2 diabetes (those who recovered from COVID-19 infection) depending on the presence or absence of non-alcoholic fatty liver disease (further – NAFLD) and malnutrition. Materials and methods: We investigated 18 patients with type 2 DM, who were included in the first group of the patients examined; group 2 consisted of 20 patients with type 2 DM and non-alcoholic fatty liver disease (NAFLD), namely with non-alcoholic steatohepatitis; and group 3 of the patients examined consisted of 30 patients with type 2 DM and obesity. Results: Renal damage in patients with metabolically associated diseases in the background of respiratory disease due to COVID-19 infection was also indicated by changes in urine test indicators, and namely – proteinuria and erythrocyturia, leukocyturia in urine sediment. The examination of cystatin C (Cys C) level indicates its statistically significant increase in patients of all examined groups, with the highest levels established in group 3 patients (with its increase up to 2.58 ± 0.11 mg/L, compared with the norm of 0.75 ± 0.04 mg/L in the control group – p < 0.01). The examination of GFR by calculation, where the Cys C index in serum was used, revealed a significant decrease in this parameter in all the examined groups of patients. At the same time, the maximum values were found in group 1 patients (65.7 ± 1.4 ml/min per 1.73 m2 of the body surface), and the minimum values – in group 3 patients (48.3 ± 2.7 ml/min per 1.73 m2 of the body surface). Conclusions: An increase in serum cystatin C levels was determined in type 2 diabetes patients, with the lowest level in group 1 patients (1.24 ± 0.07 mg/L – p < 0.05), and the highest level in patients suffering from type 2 diabetes combined with NAFLD and obesity (2.58 ± 0.11 mg/L – p < 0.01). A moderate to severe course of COVID-19 infection in patients with type 2 diabetes as well as with its combination with NAFLD and obesity contributes to the development of renal functional disorders in these patients. Moreover, an increase in serum Cys C levels is a more sensitive and earlier marker of renal damage development in comorbid pathology.